The pair bickered with such frequency and ferocity at the downtown studios of WFAA, the ABC affiliate in Dallas, that it was often hard to hear — let alone understand— either one of them. Trailing badly in the polls and in fundraising, Sadler came out swinging, saying Cruz’s suggestion that the Obama administration supports entitlement programs because it makes people dependent on government and therefore likely to vote Democratic was “the craziest thing I’ve ever heard in my life.”

When he kept up the verbal assault, an exasperated Cruz quipped, “We’re only a few minutes into it, and you’ve called me now three times crazy.”

In the first of two scheduled debates before next month’s election, Cruz and Sadler sat facing one another in a round-table format intended to encourage back-and-forth exchanges. But the two moderates repeatedly admonished Sadler to let Cruz finish his answers.

The pair is vying to replace retiring Republican U.S. Sen. Kay Bailey Hutchison, but the race looks like a cake walk for Cruz. A poll released hours before the debate by Texas Lyceum, a nonpartisan, statewide leadership group, showed the Republican leading Sadler 50 percent to 24 percent among Texans surveyed — though it also showed that 26 percent of participants were undecided.

A Democrat has not won statewide office in deeply conservative Texas since 1994.

Sadler called Cruz’s support of building a fence the entire length of Texas’ border with Mexico, and other hardline border policies, the worst of anyone who has run for the Senate.

But the most heated moment came when Sadler tried to accuse Cruz of not supporting the bid of Texas’ other U.S. Senator, John Cornyn, for a leadership position in the Senate if Republicans capture the majority in November — which triggered an exchange in which Sadler called Cruz a “troll.”

“I’m sorry, Mr. Sadler, you believe I’m a troll,” Cruz, who is quite a bit shorter than Sadler, deadpanned.

After the debate, Sadler said, “I probably should not have used the word ‘troll,’ but it’s hard when someone keeps not telling the truth.”

A former Ivy League debating champion, Cruz argued cases on behalf of Texas as the state’s longest-serving solicitor general, from 2003 until 2008.

Also an attorney, Sadler represented East Texas in the state House from 1991 until 2003. He often worked with Republicans and helped bolster local authority for school districts but also backed increasing teacher salaries while reducing property taxes.

Sadler said before the debate that he would expose his opponent as too extreme for Texas moderates or even mainstream politics. He cited Cruz’s positions on border policy and accused him of failing to support safeguarding Social Security and Medicare, as well as his calls to shutter the U.S. Department of Education and repeal every aspect of the White House-backed health care law.

But Cruz beat him to the punch a bit, saying early on that Social Security was a “critical safety net that our society is counting on” and that the nation’s elected leaders would have to “step up” to protect it.

Sadler also tried unsuccessfully to press Cruz on whether he believes President Barack Obama was born in the United States and is a Christian.

The moderates questioned Sadler about his past statements that Congress will have to examine eliminating some of the tax cuts championed by the administration of President George W. Bush in order to reduce the national debt. With that, Cruz congratulated Sadler for his “courage” in running what he called “an unapologetically liberal campaign.”

“Do you consider it liberal to say we have to pay down the national debt?” Sadler shot back.

Cruz pressed on, saying that Sadler’s support of scrutinizing the Bush tax cuts was tantamount to considering “raising taxes on every single Texan who pays income taxes.”

Cruz is now the prohibitive favorite but was the underdog in the Republican primary against long-serving Lt. Gov. David Dewhurst. Championed by grassroots groups and tea party activists, however, Cruz was able to embrace a conservative, anti-establishment mantra and won a July runoff election marked by low turnout.

Cruz has since mended fences with traditional Republicans, attending recent fundraisers with Dewhurst and the lieutenant governor’s most high-profile backer during the bitter primary campaign, Gov. Rick Perry.